The present invention relates to an improvement in a conversion kit for allowing a 5.56 mm NATO or 7.62.times.39 AR-15 or M-16 rifle to fire a 9 mm parabellum equivalent. Conversion kits for converting a M16 rifle for firing a 9 mm round are known. Such kits include a barrel replacement assembly which quite readily can be replaced for the standard M-16 round. However, the conversion of such a M-16 rifle further must include a more evasive change in the structure of the magazine receiver.
As illustrated in the prior art showing of FIG. 3, a lower receiver frame, such as provided for in an M-16 rifle is illustrated as generally 1, was modified by using front and rear mounting adapter plates 4 and 6 which were secured through adapter pins 8, 8 slid transversely through the rifle frame 2 and into the respective adapter plates. This process involved the custom forming of drill holes through the frame and the aligning of respective ones of the adapter plates with these holes to secure each of the plates within the magazine receiver. However numerous problems associated with this type of modification were prevalent. First, since the process involved aligning and drilling each frame to be individually adapted to receive the pins 8,8, the possibility for error as between one frame and the other was high. Thus, the initial process of conversion to a short round magazine was a highly involved process requiring detailed attention of a skilled worker. Additionally, even after this was done, such prior art kits were not very well adapted for field conversion requiring the insertion of the small securement pins through the drill holes once alignment could be made. Another drawback to such prior art systems, as can be seen from FIG. 3, was that the adapter plates 4,6 only provided bearing surfaces for the front and rear sides of the smaller round cartridge used. This contributed to a somewhat unstable condition when the short round magazine cartridge was situated within the magazine receiver.
Accordingly, an object in the invention to provide an adapter for a rifle enabling it to fire a shorter round and which adapter is capable of being readily inserted to the receiver of the rifle without use of pins or other like fastening devices which need to be aligned with one another.
Still a further object of the invention is to provide an adapter the aforementioned height which is capable of receiving a standard magazine cartridge of a shorter length.
A further object of the invention is to provide a conversion adapter of the aforementioned height wherein the standard cartridge release is capable of being used for removably inserting a standard 9 mm magazine cartridge repeatedly into and out of the rifle receiver.
It is still a further object of the invention to provide a converter adapter which is capable of using the spring energies found within the magazine cartridge and the rifle bolt catch to effect bolt blocking.
Still a further object of the invention is to provide a converter adapter of the aforementioned type wherein the cartridge is supported on four sides.
Further objects in advantages of the invention will become apparent from the following detailed description and the amended claims.